A 3rd generation partnership project long term evolution (3GPP LTE) (hereinafter, referred to as ‘LTE’) and LTE-advance (hereinafter, referred to as ‘LTE-A’) communication system which is an example of a wireless communication system to which the present invention can be applied will be described in brief.
FIG. 1 is a diagram illustrating a network structure of an Evolved Universal Mobile Telecommunications System (E-UMTS) which is an example of a mobile communication system.
The E-UMTS is an evolved version of the conventional UMTS, and its basic standardization is in progress under the 3rd Generation Partnership Project (3GPP). The E-UMTS may also be referred to as a Long Term Evolution (LTE) system. For details of the technical specifications of the UMTS and E-UMTS, refer to Release 7 and Release 8 of “3rd Generation Partnership Project; Technical Specification Group Radio Access Network”.
Referring to FIG. 1, the E-UMTS includes a User Equipment (UE), a base station (eNode B; eNB), and an Access Gateway (AG) which is located at an end of a network (E-UTRAN) and connected to an external network. Generally, the base station may simultaneously transmit multiple data streams for a broadcast service, a multicast service and/or a unicast service.
One or more cells may exist for one base station. One cell is set to one of bandwidths of 1.25, 2.5, 5, 10, and 20 MHz to provide a downlink or uplink transport service to several user equipments. Different cells may be set to provide different bandwidths. Also, the base station controls data transmission and reception for a plurality of user equipments. The base station transmits downlink (DL) scheduling information of downlink data to the corresponding user equipment to notify the corresponding user equipment of time and frequency domains to which data will be transmitted and information related to encoding, data size, and hybrid automatic repeat and request (HARQ). Also, the base station transmits uplink (UL) scheduling information of uplink data to the corresponding user equipment to notify the corresponding user equipment of time and frequency domains that can be used by the corresponding user equipment, and information related to encoding, data size, and HARQ. An interface for transmitting user traffic or control traffic can be used between the base stations. An interface for transmitting user traffic or control traffic may be used between the base stations. A Core Network (CN) may include the AG and a network node or the like for user registration of the user equipment UE. The AG manages mobility of the user equipment UE on a Tracking Area (TA) basis, wherein one TA includes a plurality of cells.
Although the wireless communication technology developed based on WCDMA has been evolved into LTE, request and expectation of users and providers have continued to increase. Also, since another wireless access technology is being continuously developed, new evolution of the wireless communication technology will be required for competitiveness in the future. In this respect, reduction of cost per bit, increase of available service, use of adaptable frequency band, simple structure, open type interface, proper power consumption of the user equipment, etc. are required.
Recently, standardization of the advanced technology of the LTE is in progress under the 3rd Generation Partnership Project (3GPP). In this specification, the advanced technology will be referred to as ‘LTE-A’. One of the important differences between the LTE system and the LTE-A system is the difference in system bandwidth and introduction of a relay station.
The LTE-A system aims to support a broad bandwidth of maximum 100 MHz. To this end, the LTE-A system uses the carrier aggregation (CA) technology or the bandwidth aggregation technology, which achieves a broad bandwidth by using a plurality of frequency blocks.
The carrier aggregation (CA) uses a plurality of frequency blocks as one large logic frequency bandwidth to use a wider frequency bandwidth. A bandwidth of each frequency block may be defined on the basis of a bandwidth of a system block used in the LTE system. Each frequency block is transmitted using a component carrier.
As described above, although the CA is introduced and a plurality of component carriers are configured for the user equipment, a method for transmitting an uplink control channel if TDD (time division duplex) downlink/uplink configurations are configured differently among the plurality of component carriers has not been suggested specifically. The present invention is intended to suggest the method.